Cell Membrane 2024-2025 PDF

Cell Boundaries  Cell Boundaries Cell Membrane Cell Wall Found in all cells Found in plant cells, fungal cells, bacteria cells (*protist cells) Flexible...

Cell Boundaries  Cell Boundaries Cell Membrane Cell Wall Found in all cells Found in plant cells, fungal cells, bacteria cells (*protist cells) Flexible Rigid Regulates what enters and exits; boundary, Provides structure and support cell communication Made of phospholipids, cholesterol and Made of strong chains of polysaccharides proteins Plants = cellulose Fungus = chitin Bacteria = peptidoglycan  Functions of Cell Membrane 1. Barrier between the cytoplasm (fluid in cell) and the external fluid environment 2. Semipermeable - allows certain substances to cross while preventing others 3. Cell identification 4. Cell communication (receive and send signals) Phospholipids https://www.youtube.com/watch?v= CNbZDcibegY  polar/hydrophilic Phospholipids Phosphate ▪ Phosphate head “attracted to water” ◆ hydrophilic ▪ Fatty acid tails Fatty acid ◆ hydrophobic ▪ “repelled by water” Arranged as a bilayer nonpolar/hydrophobic Aaaah, one of those structure–function examples Plasma/Cell Membrane Carbohydrate chain Integral proteins  maintains proper membrane consistency ○ keeps membrane firm, but fluid. Glycoproteins (Cell ID tags) O, A & B are representative of different types of glycoproteins on the surface of RBC  Receptor Proteins Chemical signal Chemical signals Extracellular fluid Receptor proteins Peripheral protein - relays signal inside the cell Receptor protein cytoplasm  Receptor proteins View of a signalling molecule (orange) binding to a protein receptor on the outside of the cell Cytoskeleton and peripheral proteins Cytoskeleton filaments Intracellular fluid Peripheral protein - cytoplasm helps to anchor cytoskeleton FLUID MOSAIC MODEL OF CELL MEMBRANE FLUID - because individual phospholipids and proteins can move laterally within the bilayer (like a liquid) MOSAIC - because of the pattern produced by the scattered protein molecules when the membrane is viewed from above Not all cells signal have the same proteins or the same Peripheral number of protein - relays proteins response to embedded cell interior in their membranes. The proteins a cell has determines what that cell can do. glycoprotein  Passive Transport Active Transport Diffusion: solutes moving from Solutes are actively concentrated higher concentration to lower on one side of the membrane - concentration across the membrane requires ATP energy - Polar solutes - Ions (+/-) Nonpolar solutes Channel protein Protein Pump Structure Description/Function(s) Diagram Phospholipids Glycoproteins Receptor proteins Peripheral proteins Peripheral Cholesterol cholesterol Structure Description/Function(s) Diagram Protein Channel (transport protein) Protein Pump